Models for Mobile Application Maintenance Based on Update History

Xiaozhou Li, Zheying Zhang and Jyrki Nummenmaa

School of Information Sciences, University of Tampere, Kalevantie 4, FI-33014, Tampere, Finland

Keywords:

Software Maintenance, Software Release, Mobile Application, Maintenance Model.

Abstract:

Good software development and particularly maintenance practices form an important factor for success in

software business. If one wants to constantly produce new successful releases of the applications, a proper

efﬁcient software maintenance process is the key. In this work, we study data from mobile application main-

tenance to understand and conceptualize how mobile application maintenance takes place. Based on the data

on release history, we deduce different mobile application maintenance models from the perspectives of main-

tenance scheduling and maintenance requirements.

1 INTRODUCTION

Mobile devices have evolved into multi-functional

mobile personal processors, with a wide variety of

functionalities and software. Rapid development is

often connected to ﬁerce competition, which, con-

versely, is also the main driving force of development.

So far, together with the development of the mobile

device market, competition between mobile platforms

has brouhgt the evolution of mobile devices and their

software to a new level. The number of mobile appli-

cations has increased tremendously with the applica-

tions rapidly expanded into a wide range of domains.

Different from traditional software-intensive sys-

tems, mobile applications are often written specially

to utilize the unique features a particular mobile de-

vice offers. Most applications were developed cre-

atively satisfying unrevealed needs of users instead of

complying with a speciﬁc client’s expectations. It is

not uncommon to change requests from users’ feed-

back after the applications are brought to market. In

addition, as the mobile platforms are evolving very

quickly, an application needs some adaption or mod-

iﬁcation when new versions of operating systems are

released. All these make the maintenance and evolu-

tion of a mobile application a critical process.

Good software development and particularly

maintenance practices form an important factor for

success in software business. Software mainte-

nance in general is both time and money consum-

ing (Boehm, 1984). If one wants to constantly pro-

duce new successful releases of the applications, a

proper efﬁcient software maintenance process is all-

important. However, current research related to mo-

bile application maintenance is still limited.

In this paper, we study data from mobile appli-

cation maintenance to understand and conceptualize

how actual maintenance occurs. The major hypoth-

esis is update history of existing mobile applications

could show processes that mobile applications share

when being maintained, and methods for mobile ap-

plication maintenance could be deduced from analy-

sis of the collected update history data. Thus, based

on the observed patterns, we propose three mainte-

nance models. With the help of conceptualization of

these initially implicit models, we expect that not only

do we better understand the mobile application main-

tenance, but the models can also be explicitly used

in conducting future mobile application maintenance.

The update history data, including update time span

and content, are collected from Apple app store.

The remainder of the paper is organized as fol-

lows. Section 2 gives some background on software

maintenance terms and process description. Section

3 introduces our data collection method and analysis

process. Section 4 presents the research ﬁndings of

three maintenance methods for mobile applications.

Section 5 contains discussion and conclusions.

2 BACKGROUND

2.1 Software Maintenance

The software maintenance phase covers the whole

procedure ranging from the delivery of the software

to its retirement. Martin and McGlure deﬁne software

212

Li X., Zhang Z. and Nummenmaa J..

Models for Mobile Application Maintenance Based on Update History.

DOI: 10.5220/0004952102120217

In Proceedings of the 9th International Conference on Evaluation of Novel Approaches to Software Engineering (ENASE-2014), pages 212-217

ISBN: 978-989-758-030-7

 2014 SCITEPRESS (Science and Technology Publications, Lda.)

maintenance as ”Changes that have to be made to

computer programs after they have been delivered to

customer or user” (Martin and McClure, 1983). Soft-

ware maintenance is also deﬁned as ”the modiﬁcation

of a software product after delivery to correct faults,

to improve performance or other attributes, or to adapt

the product to a modiﬁed environment”(IEEE, 1998).

Software maintenance forms an increasingly impor-

tant part in the development and evolution of software

engineering theory and practice. However, it is also

expensive and time-consuming. The modiﬁcation of

software product could take up a percentage ranging

from 40% to 70% of the total cost of the software life

cycle (Hunt et al., 2008).

There are four types of software maintenance

practices, i.e. Corrective maintenance, Adaptive

maintenance, Perfective maintenance, and Preventive

maintenance. Corrective maintenance refers to acts

in order to correct errors detected after software re-

lease. Adaptive maintenance is to adapt software to

newly changed system environment (Swanson, 1976).

Perfective Maintenance is to enhance existing fea-

tures and improve the general performance of soft-

ware (Singh and Goel, ).

The fourth maintenance type, Preventive mainte-

nance, deﬁned as modiﬁcation in order to prevent a

software system from future crash and enhance the

maintainability and credibility (Ger

ısbakh, 1977) is

of great importance as well, however, it will not be

further discussed in this paper. This is because we

assume that preventive practices, such as refactoring

(Fowler, 1999), can not be seen as visible changes

from users’ view but should be carried out through-

out the whole maintenance process. In addition, we

deﬁne in this paper maintenance requirements as the

requirements that after software release specify how

the software should be updated. Maintenance require-

ments encompass the three types of maintenance and

also requirements for additional features.

2.2 Mobile Application Maintenance

Under the background of current competition-

intensive mobile application market, the daily in-

creasing rate of new applications is tremendously

high while numbers of applications aiming for the

same user group and sharing the same functionali-

ties. Thus the products that constantly providing con-

tinuous high quality and exciting new features from

time to time will take the leading position and be

recognized by more potential users. Concerning the

improvement of software quality, methodologies are

supposed to contribute to either the product itself or

the process (Sommerville, 2007). Maintenance for

mobile application is aiming to maintain the high

quality and stable performance. The improvement

of mobile maintenance process is therefore of great

importance accordingly. To better organize the pro-

cess of mobile application maintenance coping with

the competition and unpredictability of the market, a

maintenance schedule, which is deﬁned as the contin-

uous planning timetable for mobile application main-

tenance process, should be used as one of the tools.

Besides coping with the maintenance require-

ments of previously mentioned types, occasionally

adding new features to existing software is of great

importance to mobile applications. We deﬁne a new

feature as a new type of service or new experience

provided by the application, such as avatars, game

themes, rewards, tasks, and so on. Despite of the

fact that adding new features is somehow considered

as part of perfective maintenance (Hatton, 2007), we

emphasize the importance of adding new features in

mobile application maintenance phase and consider it

a unique maintenance type besides the existing four.

Concerning the Kano’s model of customer satisfac-

tion (Berger et al., 1993), attractive requirements,

which provide users unexpected new features, boosts

user satisfaction most sharply. Additionally, provid-

ing one-dimensional features, results in proportional

user satisfaction increase (Sauerwein et al., 1996).

The importance of adding new features in mobile ap-

plication maintenance phase is indisputable, and the

maintenance process lasts till the software closedown.

Resulting from the variety of user feedbacks

and unpredictability of market trends, the mainte-

nance should be organized iteratively (Choudhari and

Suman, 2010). Therefore, a well-organized mainte-

nance schedule including a reasonable new feature

updating frequency is important, and that schedule

should be well planned for mobile application main-

tenance.

Considering maintenance process in general as

one stage, that stage shall contain components or

properties including objectives, inputs and outputs,

and methods (Sommerville, 2007). A mobile appli-

cation maintenance process can be simply depicted as

what is shown in Figure 1. Before the actual main-

tenance process starts, certain input conditions must

be clariﬁed, taking into account possible inﬂuencing

factors. For example, mobile application business

models (Vannieuwenborg et al., 2012), objectives and

market trends inﬂuence the choice of maintenance re-

quirements. The situation of maintenance team and

customers, on the other hand, affects the organiza-

tion of maintenance schedule. Feedback from end

users provides simultaneously maintenance require-

ments and schedule managing guidelines.

ModelsforMobileApplicationMaintenanceBasedonUpdateHistory

213

Taking all input information into account, the

maintenance process is an iterative process (Bennett

and Rajlich, 2000) of working on certain amount of

maintenance requirements (the objectives), according

to the maintenance schedule with a certain mainte-

nance method (the method of managing maintenance

requirements and schedules). Apparently, the out-

come of maintenance work comprises application re-

leases with updated content, recorded in update his-

tory. The recorded release dates suggest a mainte-

nance schedule while update content shows which

maintenance requirements are fulﬁlled. Thus, we

are investigating the possibilities to deduce possible

maintenance models based on the update history.

Figure 1: General Process Model of Mobile Application

Maintenance.

3 COLLECTION AND ANALYSIS

OF UPDATE HISTORY DATA

As a basis of our analysis, we will consider the re-

alized maintenance schedules of mobile applications.

We primarily try to combine the schedule information

with the information on new features in the releases,

in order to ﬁnd maintenance patterns. Appropriately,

the application update history of iOS(iPhone Operat-

ing System) applications provides information con-

cerning the update content and update time of each

application, which is more accessible from Apple app

store than that from Google Play Market

. Thus, we

collected the update history data of 100 mobile ap-

plications covering different categories on iOS plat-

form. As shown in Figure 2, from the screenshot of

the update history, it is easy to identify information

concerning release date and update content.

The application market regions that we chose to

investigate are the USA and China as the application

store from the USA region contains by far the most

available applications, and China has the most rapidly

increasing number of applications on the Apple app

store. However, how cultural factors inﬂuence the

process of mobile application maintenance is not our

current focus but belongs to the future work. More-

over, the fact that the two countries differ from each

https://play.google.com/store.

Figure 2: Update History Screenshots of NinJump HD,

Subway Surfers, and Foursqure from iTunes.

other in terms of customs and culture in many ways

means that any ﬁndings or universal patterns found

are not just a phenomena of a single country.

Taking into account the validity of data, we se-

lected applications that conform to the following re-

striction: the application should have at least ﬁve up-

dates or has been delivered in Apple app store for

at least two years if it has no less than ﬁve updates.

When there were more than 15 updates after the ﬁrst

update in 2012, we considered only the updates since

2012. Based on the update history, the value of time

span (TS) of each update was calculated as the differ-

ence of two consecutive release date. The time span

standard deviation (TSSD) reﬂects the organizational

level of the maintenance schedule.

By analyzing the update content we can ﬁnd

whether new features (NF) were implemented in a

certain update. The aim of our data analysis was to

ﬁnd the correlation between the maintenance meth-

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ods and the two parameters concerning the frequency

of adding new features and the consistency of update

time span. Thus, we used the value 1 for updates with

new features implemented and 0 for updates without

new features. The Average New Feature Update Fre-

quency (ANFUF) is the arithmetic mean of assigned

new feature update parameter NF (NF = 0 or 1) of

selected updates. The collected data of NF and TS

from the three sample applications is presented in Ta-

ble 1. The data representing the part of update history

in Figure 2 is marked in bold italic font.

Table 1: Update Data Examples.

NinJuam HD Subway Surfers Foursquare

TS NF TS NF TS NF

15 0 38 1 10 0

35 0 10 0 11 0

169 1 35 1 13 1

5 0 28 1 2 0

48 0 25 1 12 0

12 0 10 0 13 1

53 0 13 1 11 1

106 0 21 1 10 0

215 0 1 0 9 1

67 0 9 0 17 0

67 0 10 1 8 0

... ... 25 1 11 1

20 1 15 0

7 0 10 0

13 1 19 0

20 1 8 0

... ... 12 1

... ...

The formula for arithmetic mean is

ANFUF =

∑

i=1

NF, where NF = 0 or 1

The other variable is the Time Span Standard Devia-

tion (TSSD), which is simply the standard deviation

of all update time spans (x) as below.

T SSD =

∑

i=1

− µ)

, where µ =

∑

i=1

When calculating time span, a business day calcula-

tion web application (Timeanddate, 2014) is used in

order to exclude weekends and public holidays. By

setting two variables for each mobile application, all

selected applications could be located in chart with

TSSD as x-coordinate and ANFUF as y-coordinate,

which is presented as Figure 1.

We can make some initial observations directly

from Figure 3. First of all, a majority of application

samples locate in the division where TSSD is lower

Figure 3: Statistics concerning the Relation of TSSD and

ANFUF.

than 30 and ANFUF is higher than 0.5. It shows that

the maintenance schedule of these applications are

better organized with at least one new feature imple-

mented within two updates. On the other hand, appli-

cations that locate in the down-right division have less

organized maintenance schedule with fewer new fea-

tures than other applications. They also have less than

half of the total update amounts compared to the other

applications. The other applications locate in the left-

down division where TSSD and ANFUF are both low,

which indicates these applications keep maintaining

though without as many new features. In addition, no

applications have both high TSSD and ANFUF as it

seems not highly possible that maintenance schedule

is poorly organized when many new features are up-

dated simultaneously.

4 MAINTENANCE MODELS

As shown in Figure 3, we divide the whole area into

four divisions by the lines of ANFUF = 0.5 and TSSD

= 30. Based on the analysis of the distribution of ap-

plication samples and the details in update history, we

deduce the following three mobile application main-

tenance models.

4.1 Emergency-oriented Maintenance

For mobile applications located in the down-right di-

vision of the ﬁgure, the maintenance is to deal with

various types of emergent issues within maintenance

phase, including bugs, system crashes, environment

adaption, as soon as possible without considering the

implementation of new features. The essential aim

of their maintenance phase is to maximally maintain

the stability of applications in all possible environ-

ments. We name this maintenance model Emergency-

Oriented Maintenance. The process of Emergency-

ModelsforMobileApplicationMaintenanceBasedonUpdateHistory

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Oriented Maintenance is to a large extent random

and spontaneous. The whole maintenance process is

more likely the extension of the debugging of pre-

vious development phase. Together with continuous

testing, debugging and refactoring, as well as incom-

ing user reviews, there are more potential bugs emerg-

ing. Thus, ﬁxing bugs is of the highest priority com-

pared with other maintenance requirements. When

the maintenance starts, maintainers cover at least crit-

ical corrective maintenance requirements ﬁrst, includ-

ing some perfective maintenance requirements if it

is possible. Additionally, whenever adaptive main-

tenance occurs, it should be promoted to the highest

level. Correspondingly, the release date depends on

the accomplished amount of bugs ﬁxed and the de-

gree of urgency.

One of the typical examples of conforming to

Emergency-Oriented Maintenance is NinJump HD

an action adventure game. The update history of this

game is presented in the ﬁrst column of Table 1. Con-

cerning the update time span of this application, it

is obvious that the time spans range from one week

to ten months, which is highly unorganized. On the

other hand, there are no new features implemented in

the whole maintenance process except for once in the

second update. Nevertheless, the stability of the game

is proven to be good according to the user feedback,

with most criticism concerning the game idea, not re-

porting critical bugs.

4.2 Feature-oriented Maintenance

The applications in the left-up division contain a high

new feature updating frequency, which shows focus

on new features. Therefore, we name the mainte-

nance model in this division Feature-Oriented Main-

tenance. Compared with Emergency-Oriented Main-

tenance, Feature-Oriented Maintenance is more orga-

nized concerning update time span. Despite of the

fact that occasionally it takes more than one month

to release an update version, the variance of the time

spans is mostly lower than 30. The main aim of ap-

plying this maintenance method is to provide constant

new features, in order to keep users attracted. Mean-

while, within each release, corrective and adaptive

maintenance requirements are included as well, tak-

ing both stability and innovation into account. How-

ever, in the case of critical bugs, an emergency release

will be delivered despite that it might to some extent

deteriorate the well-planned maintenance schedule.

Subway Surfers

is a typical example of Feature-

Oriented Maintenance. The update history of this

http://www.backﬂipstudios.com/games/ninjump/.

http://kiloo.com/games/subway-surfers.

game and an excerpt the screenshot is brieﬂy pre-

sented in Table 1 and Figure 2. We could easily ob-

serve that except for bug ﬁxing minor updates, each

major update of this application contains one brand

new theme as well as relevant other new items. Con-

cerning the update span, each update takes approx-

imately one month, which is much more organized

than NinJump HD. In addition, continuously updat-

ing with new themes and features results in accord-

ingly positive feedbacks and high popularity.

4.3 Constant Maintenance

The applications located in the left-down division

have low time span variance without a high new fea-

ture implementation rate. The maintenance schedule

is like in Feature-Oriented Maintenance, but with fo-

cus on the process organization than new feature im-

plementation. We call this maintenance model Con-

stant Maintenance. Constant Maintenance model is a

regular but disciplined maintenance model that does

not consider updating new features as the ﬁrst prior-

ity. The empahsis is on constantly organized main-

tenance process. Compared to the other two main-

tenance models, this maintenance model is similar

to the idea of applying agile principles (Beck et al.,

2001) in maintenance phase. The whole maintenance

process is constantly divided into maintenance itera-

tions with durations of normally 10 to 20 days. Each

of the maintenance iterations covers corrective main-

tenance requirements of highest priority as much as

possible and occasionally perfective maintenance re-

quirements and new features. Adaptive maintenance

requirements are of high priority whenever appearing.

Constant Maintenance model requires no speciﬁc

new features in each update as routines. New features

could be added when it is needed and planned in a

certain update. On the other hand, the time span of

updates is required to be short. This model will re-

sult in a maximally organized maintenance process.

However, the effort and cost spent on planning will

be higher as well.

Foursquare

is a typical application in this cate-

gory, with it’s update history presented in the third

column of Table 1. The update history shows that

each update span lasts around 15 days. Each update

implements all possible types of maintenance require-

ments as well as new features with certain deﬁned pri-

oritizing preference.

https://foursquare.com/.

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5 CONCLUSIONS

This paper introduces three mobile application main-

tenance models based on the analysis of mobile ap-

plication update history. We collected data to iden-

tify the new feature update frequency and standard

deviation of update time span. By studying the dis-

tributions of these two variables for sample mobile

applications, we observed the patterns of how exist-

ing mobile application maintenance works. The sum-

marized three mobile application maintenance mod-

els form the basis of future research to study explicit

and thorough deﬁnitions, instructions and guidelines,

which could be further used in maintenance practice.

The three proposed models provide promising ways

to organize better maintenance schedules and mainte-

nance requirements.

Our future research concerning mobile applica-

tion maintenance will focus on constructing mainte-

nance process model for mobile applications based

on the three maintenance methods obtained from pre-

vious ﬁndings. Traditional software maintenance

process models have been widely studied and uti-

lized (Ren et al., 2011). Considering the defects of

heavyweight maintenance practices and speciﬁc re-

quirements of current mobile applications, an agile

lightweight maintenance process model could be a

more efﬁcient and economical solution. Related re-

search has been done concerning the result of in-

troducing XP practices to software maintenance pro-

cess. The positive results indicate it could be success-

ful introducing agile practices into software mainte-

nance process (Svensson and Host, 2005). Further-

more, concerning the construction of mobile appli-

cation maintenance models, there are also more de-

tailed research areas to be taken into account, includ-

ing methodologies of eliciting maintenance require-

ments from user feedbacks, managing maintenance

requirements, applying agile principles in mobile ap-

plication maintenance practices, and so on. Further

research should also include bigger samples with ap-

plications from other platforms.

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Appendix of the mobile applications update his-

tory data available upon request.

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